When Nowitzki didn't get it, the Dallas Mavericks could only settle for another frustratingly close loss and an uphill climb to survive in their first postseason since winning the NBA title.

Russell Westbrook scored 29 points, Durant added 26 in an off-shooting performance and Oklahoma City clawed out a 102-99 victory over Dallas on Monday night to take a 2-0 series lead.

The Mavs led in the final minute of both games in Oklahoma City but couldn't even manage a split as the Thunder gutted out two wins by a total of four points.

"That's what the playoffs are about," Westbrook said. "Toughness."

Durant hit two free throws with 50.4 seconds left to give Oklahoma City a 98-97 lead, and James Harden hit four more foul shots to close it out for the Thunder.

Jason Terry missed two 3-point attempts from the left wing in the final 5 seconds that could have tied it and set up overtime.

"We come away from these two games disappointed but not dismayed. You tip your hat to the fact that they have made some big time plays," Dallas coach Rick Carlisle said. "Now, we've got to go home and do the same."

Game 3 is Thursday night in Dallas.

"We're just a couple bounces away from being up 2-0," said Nowitzki, who led Dallas with 31 points but missed both his shots in the final 75 seconds.

"It's tough and it's frustrating, but we're going to keep coming. We're not going to lay down. If they beat us, we're going to make them earn it."

Durant put the Thunder ahead to stay after salvaging two key points with Oklahoma City inbounding the ball with only 2.6 seconds left on the shot clock. He grabbed the inbounds pass from Harden while headed toward the sideline, and Terry was called for a foul for bumping him.

Durant hit both foul shots, and Nowitzki missed his chance to answer with a fadeaway 12-foot jumper from the left side. He compared it to Durant's foul-line jumper -- on which he later admitted he couldn't even see the rim -- that hit the front rim and backboard before falling in with 1.5 seconds left to win Game 1.

"I've made it 100 times. It bounced, hit every part of the rim and bounced off," Nowitzki said. "That's kind of the way our season's been going.

"They get that bounce last game and we don't get it, so that's frustrating."

After that, the Mavs were fighting from behind.

Shawn Marion fouled Harden on the rebound, and the league's top scoring reserve -- only eight days removed from a concussion suffered as the result of Metta World Peace's elbow to the head -- also converted both free throws. He hit two more with 15.6 seconds left after Terry got the Mavs within one with a driving layup.

"We've just got to continue to take that punch from them and do a great job of sticking together," Durant said. "Games like this in the playoffs, they're going to get chippy and we know that. So, we've just got to play through it.

This one nearly came to blows, literally.

The tension escalated quickly after Serge Ibaka tried to block Nowitzki's jumper midway through the first quarter and smacked him in the left eye on his follow-through, without getting called for a foul. Nowitzki hit another jumper along the baseline on Dallas' next possession before he got shoved in the back by Kendrick Perkins while jockeying for rebounding position on a made 3-pointer by Durant.

Perkins followed Nowitzki for a few steps before Nowitzki bumped him away, and Perkins responded by taking a swing at Nowitzki's head with his open hand. Official Zach Zarba stepped in front of Perkins and backed him away, and both were assessed technical fouls.

"He tried to bully me and I bullied back a little bit and talked about some stuff, and moved on," Nowitzki said.

The Thunder erupted a few minutes later, scoring the final nine points of the first quarter -- all within an 82-second span -- and then carrying over the momentum to build a 46-30 lead with 5:55 left before halftime.

When Nowitzki and Perkins finally got back on the court together, the Mavericks' All-Star exacted some revenge while getting his team back in the game. He went on a personal 10-2 run, with all of the points coming while he was matched up against Perkins, to get the deficit down to 50-47.

"It's playoff basketball. It's physical. We don't like the cheap shots when they give them, and they don't like them if we give them. That's the nature of competition," Carlisle said. "I love hard-played, clean, competitive playoff series. You throw the ball up and may the best team win.

"The dirty (expletive) has got to stop. We don't want anybody getting hurt out there, either way."

Game notes
After going back and forth responding to each other's comments on how Oklahoma City's defense on Nowitzki was officiated in Game 1, Thunder coach Scott Brooks insisted any dispute with Carlisle wasn't personal. Years ago, the two roomed together while playing in the Continental Basketball Association. "He was a good roommate. He didn't snore," Brooks said. "That's all it takes. Buy me a meal every now and then and not snore, you're a perfect roommate." He later playfully retorted: "If you want it to be personal, I was a better player. How many years did I play in the league? How many years did he play? I played over a decade. He played three." ... Marion hadn't made a playoff 3-pointer since 2007 before making two in Game 1. He had another in Game 2. ... Ibaka, who tied his regular season best with 22 points in the first game, got into foul trouble and scored only two.